In power and electronic fields, power converters are required to have high efficiency, high power density, high reliability and low cost. High efficiency means less energy consumption, less cost and being benefit for energy conservation, emission reduction, and environment protection. High power density means being small and light, which may reduce transportation cost and space requirement as well as reduce material cost, thusly reduce construction cost. High reliability means longer service life and lower maintaining cost.
To meet the development trend of power converting module, modularization of power devices become an important development trend. The power module package is developed to be light, slight, short and small, which is an important development direction, however, it has problems in heat dissipating and insulating distance.
Besides, to a packaging module of the power converting circuit based on a direct bonding copper (DBC) substrate or a metallized ceramic substrate, generally one-hole-one-module structure is adopted during plastic packaging. As a result, the plastic packaging mould has to be changed when the module size is changed accordingly. Since the cost of mould is tens of thousands to hundreds of thousands of US dollars, the production cost of the packaging module of the power converting circuit is very high. In actual operation, to avoid overmuch cost of plastic packaging mould, the universality of mould is usually considered during designing. However, this limits the designing and makes it unable to achieve the optimization design.